Cooling of moving strip



La A May 9, 1961 w. H. BAILEY, JR 2,983,497

cooLING oF MOVING STRIP Filed Feb. 1. 1954 l i: =\J

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w.H. DAILEY JR.

HIS ATTORNEY cooLlNG oF MovlNc srnrr States Patent William H. Dailey, Jr., Toledo, Ohio, assignor, by mesne assignments, to Midland-Ross Corporation, Cleveland, Ohio, a corporation of Ohio Filed Feb. 1, 1954, Ser. No. 407,322

Claims. (Cl. 263-3) This invention relates to cooling of strip, such as strip and at an unbalanced temperature condition, and thereafter cooling to a relatively elastic state, bringing the strip to a balanced temperature condition, and forming wrinkles in the strip.

When hot strip whose edges are hotter than its center is stretched flat, then cooled, the edges of the strip contract more than the center and leave a wrinkled center and a straight edge. This can be fairly easily corrected by stretching, since it is usually arelatively small area at the edge of the strip which kmust be stretched.

When it is the center of the strip which is hotter when the strip is stretched flat at high temperaure, then upon cooling the edges become ruiiied, and this conditionv is practically impossible to correct by the expedient of stretching due to the relatively large center area to be stretched. This is' the condition most often met on rapid cooling, and this invention is primarily designed to avoid this type of difliculty by providing for most effective applied cooling in the center area of the strip to compensate for the natural tendency of the edges to cool fastest in a closed cooling chamber.

To apply a diiferential cooling effect side to side of the strip and compensate for the inherent cooling characteristics of the apparatus or cooling chamber, a series or bank of longitudinally extending, internally iluid cooled tubular heat sinks is provided, above and below the strip being preferred, and the cooling ow of iluid is adjusted individually, or from tube to tube, to provide a differential applied cooling effect side to side of the strip.

For a further consideration of what I believe to be novel and my invention attention is' directed to the following portion of this specification, the drawing and the claims forming part thereof.

In the drawing:

Fig. l shows a sectional, elevational view of apparatus according to this invention.

Fig. 2 shows a sectional, plan view of the apparatus.

The improved cooling apparatus is illustrated as a part of a modern continuous' galvanizing line for strip steel wherein the strip, represented by a discontinuous line 10, leaving a high temperature cleaning and atmosphere annealing chamber, passes through an entry zone 11, which may include an atmosphereseal, into a cooling chamber 12 and thence through a discharge tunnel 15 into a molten bath of zinc 13 in a pot or tank 14 and out therefrom to further processing and cooling. Suitable rolls 16, 17 are provided to Support and advance the strip through the apparatus.

The chamber 12 is preferably formed of gas-tight welded sheet metal lined with insulation so that cooling Patented May 9, 1961 the strip. Air is caused to ow through these tubes, thus cooling the tubes and constituting the tubes heat sinks for radiation cooling of the strip. To simplify the mechanism for causing coolant air ,to flow, the tubes 2 1, 22, 23 and 24 are arranged with their respective inlet endsv at the respective ends .of the cooling chamber v1,2 and their outlet ends discharging into manifolds 25, 26 located centrally of the cooling chamber.l The manifolds 25 vand 26 lead through duct 36 to the intake side 28 of an exhauster blower 27, thus imposing a reduced pressure on the outlet ends of the tubes and causing draft therethrough to a stack 19. The tubes are thus operated at a reduced pressure, hence if any leaks developin the tubes within the cooling chamber, atmosphere from within the chamber will leak into the tubes, and the cooling chamber atmosphere will not be contaminated by the cooling air.

'I'he individual tubes are provided with ,draft controls as by valves 32, 33, 34, 35 operable manually, or the valves may be operated automatically responsive to downstream strip temperature. The individual tubes may be each provided with a fuel nozzle at its yinlet end,ylike nozzles 31 shown at the inlet of tubes 21, constituting the tubes heaters for initial warming of the cooling chamber, and the valves 32 are then vutilized to-control draft through the tubes to obtain a proper proportion of combustion air. While the air from the stack 19 may be used as preheated combustion air, its temperature is generally too low to be of value for this recuperative purpose. l v While air is the preferred vcoolant uid for internally cooling the tubes, other uids may be used where it is so desired, as for example steam, or a tine water spray in an air stream, not shown.

I claim:

1. The method of cooling continuously moving strip which comprises passing the strip through an enclosed zone while passing a fluid coolant, in a direction generally parallel to the direction of movement of the strip, through each of a plurality of conduits disposed within the enclosed zone in a bank which extends laterally thereacross, and individually controlling the rate of coolant ilow through each conduit.

2. The method of cooling continuously moving strip which comprises passing the strip through an enclosed lzone while passing a fluid coolant, in a direction parallel to the direction of movement of the strip, through each of a plurality of conduits disposed within the enclosed zone in' two banks, one above and one below the strip, each of which banks extends laterally across the zone, and individually controlling the rate of coolant ow through each conduit whereby thetemperature` of the strip is maintained substantially constant throughout any width.

3. Apparatus for cooling a continuously moving strip which comprises, in combination, wall means forming an elongate cooling chamber, means for moving the strip through said chamber from end to end thereof, a bank of heat transfer means positioned within said chamber, each of which means extends longitudinally of said chamber, while said bank extends transversely across the said cooling chamber, and means for individually controlling the heat absorbing capacity of each of said heat transfer means.

4. Apparatus for cooling a continuously moving strip which comprises, in combination, wall means forming an elongate cooling chamber having at its respective ends an inlet and an outlet for the strip, means for advancing the strip through the cooling chamber from end to end thereof, a bank of heat transfer tubes positioned Within said chamber, each of which tubes extends longitudinally of said chamber, while said bank extends transversely across the said cooling chamber, means for inducing aflow :of a cooling uidthrough'each of said tubes, and valve means for'individually controlling the rate of iidid 'flowthrough each of said tubes. Y

"5. Apparatus as claimed in claim 4 wherein upper Vand lower banks of the said heat exchange tubes are positioned in said cooling chamber, and the stripis moved between said upper and lower banks.

6. Apparatus for cooling a continuously moving strip which comprises, in combination, wall means forming an elongate cooling chamber,`means for moving the strip longitudinally through the chamber, a bank of tubes disposed in the cooling chamber, each of which tubes extends longitudinally of said chamber, while said bank extends v'transversely across the said cooling chamber, each 'of said tubes having a cooling 'uid outlet end and a cooling iiuid inlet end, lwhich inlet end communicates with atmosphere 'outside of the said chamber, exhaust means connected to the fluid outlet end of each of said tubes for inducing a flow of atmosphere therethrough, and means for individually controlling the ow of atmosphere through each of Vsaid tubes.

7. Apparatus as claimed in claim 6 which includes nozzle means Vfor delivering fuel to each of said tubes for combustion therein, and means for individually controlling the flow of fuel to each of said tubes.

8. Apparatus for cooling moving stn'p to a uniform temperature from side to side thereof which comprises, in combination, wallmeans forming an elongated cooling chamber, upper and lower banks of heat exchange tubes withinsaid chamber, each of which tubes` extends longitudinally through the cooling chamber, and each of which banks extends transversely of said chamber, means for moving strip longitudinally through`l said cooling chamber between said upper and lower banks of tubes,

means for supplying a cooling fluid to the interior of each of said tubes, means for inducing a flow of cooling uid through each of said tubes, and means for varying the rate of flow of cooling fluid through each of said tubes, independently of the rate of flow through .the othersl of said tubes, whereby to maintain in the strip a substantially uniform temperature from side to side thereof.

9. Apparatus for cooling a continuously moving strip which comprises, in combination, wall means forming an elongate cooling chamber, means for moving strip through said chamber from end to end-thereof, a bank of heat transfer means positioned within said chamber, each of which means extends longitudinally of said chamber, whilesaid bank extends transversely across the said cooling chamber, and means for individually adjusting the heat transfer means of said bank to vary the lateral cooling eiect of said bank on said strip in a manner to maintain the strip temperature substantially uniform from side to sid'e'thereof 10. Apparatus for cooling a continuously moving strip which comprises, in combination, wall means forming an elongate cooling chamber, means for moving strip through said chamber from end to end thereof, a bank of heat transfer means positioned within said chamber, each of which means extends Alongitudinally of said chamber, while said bank 'extends transversely across the said cooling chamber, and `means for varying the heat absorption of said bank relative to each of a plurality of longitudinally extending portions of the strip.

References Cited in the iile of this patent UNITED STATES PATENTS 1,551,180 Thornhill Aug. 25, 1925 1,887,504 Frost Nov. 15, 1932 1,952,402 Wilson Mar, 27, 1934 2,205,915 Wean et al. June 25, 1940 2,331,887 vBonsack Oct. 19, 1943 

